The invention relates to a circuit arrangement for a picture display device for generating a sawtooth line deflection current having a trace and a retrace through a line deflection coil, comprising a power supply transformer having a primary winding, one end of which is connected to a terminal of a supply voltage source and the other end to a controllable supply switch which is connected to the other terminal of said source and having a secondary winding to which there are coupled the series arrangement of the line deflection coil and a trace capacitor and also a deflection switch which is also controllable, and a retrace capacitor, the deflection switch being conductive in operation during the trace period and cut off during the retrace period, while the supply switch is conductive during at least a portion of the trace period and cut off during the retrace period, the line deflection coil, the trace and retrace capacitors forming part, in the retrace period, of a resonant network the elements of which determine the duration of the retrace period.
A circuit arrangement of this type is disclosed in the European Patent Application 33,678. By means of this known circuit arrangement all the supply voltages for the different portions of the picture display device, including the line deflection circuit, one be generated. If necessary, the generated voltages and the amplitude of the line deflection current can be kept substantially constant by controlling the conduction time of the supply switch. The prior art circuit arrangement also comprises a third switch arranged in series with the secondary winding of the transformer which is conductive during the period of time the supply switch is cut off and cut off during the period of time the supply switch is conductive. This means that supply energy is stored in the transformer during the time the supply switch conducts and that during the time this switch is cut off this energy is applied by the secondary winding of the transformer to the resonant network to replenish energy losses therein.